Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.
Aerobic literally means "relating to, involving, or requiring free oxygen", and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism.
Aerobic exercise or cardio, requires pumping of oxygenated blood by the heart to deliver oxygen to working muscles.
Aerobic exercise stimulates the heart rate and breathing rate to increase in a way that can be sustained for the exercise session.
Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time.
Specific equipment (such as cardio machines) may be used during aerobics, but is not necessary for successful aerobic exercise.
Aerobic/cardio exercise has long been a popular approach to achieving weight loss and physical fitness. Examples of cardiovascular/aerobic exercises include:
- Stair climbing:
Stair climbing is the climbing of a flight of stairs. It is often described as a "low-impact" exercise, often for people who have recently started trying to get in shape. A common exhortation in health pop culture is "Take the stairs, not the elevator".
- Elliptical trainer:
An elliptical trainer or cross-trainer (also called an X-trainer) is a stationary exercise machine used to simulate stair climbing, walking, or running without causing excessive pressure to the joints, hence decreasing the risk of impact injuries. For this reason, people with some injuries can use an elliptical to stay fit, as the low impact affects them little. Elliptical trainers offer a non-impact cardiovascular workout that can vary from light to high intensity based on the speed of the exercise and the resistance preference set by the user.
- Indoor rower:
An indoor rower, or rowing machine, is a machine used to simulate the action of watercraft rowing for the purpose of exercise or training for rowing. Indoor rowing has become established as a sport in its own right. The term also refers to a participant in this sport.
- Stationary bicycle:
A stationary bicycle is usually a special-purpose exercise machine resembling a bicycle without true wheels, but it is also possible to adapt an ordinary bicycle for stationary exercise by placing it on bicycle rollers or a trainer. Rollers and trainers are often used by racing cyclists to warm up before racing, or to train on their own machines indoors.
A treadmill is a device generally for walking or running or climbing while staying in the same place. Treadmills were introduced before the development of powered machines, to harness the power of animals or humans to do work, often a type of mill that was operated by a person or animal treading steps of a treadwheel to grind grain.
More recently, treadmills are not used to harness power, but as exercise machines for running or walking in one place. Rather than the user powering the mill, the machine provides a moving platform with a wide conveyor belt driven by an electric motor or a flywheel. The belt moves to the rear, requiring the user to walk or run at a speed matching that of the belt. The rate at which the belt moves is the rate of walking or running. Thus, the speed of running may be controlled and measured.
- Aerobic gymnastics:
Aerobic gymnastics or sport aerobics is a competitive sport originating from traditional aerobics in which complex, high-intensity movement patterns and elements of varying difficulty are performed to music.
Walking is defined by an 'inverted pendulum' gait in which the body vaults over the stiff limb or limbs with each step.
Sustained walking sessions for a minimum period of thirty to sixty minutes a day, five days a week, with the correct walking posture, reduce health risks and have various overall health benefits, such as reducing the chances of cancer, type 2 diabetes, heart disease, anxiety disorder and depression.
Bicycles are often used by people seeking to improve their fitness and cardiovascular health. In this regard, cycling is especially helpful for those with arthritis of the lower limbs who are unable to pursue sports that cause impact to the knees and other joints. Since cycling can be used for the practical purpose of transportation, there can be less need for self-discipline to exercise.
- Cross-country skiing:
Cross-country skiing is a form of skiing where skiers rely on their own locomotion to move across snow-covered terrain, rather than using ski lifts or other forms of assistance. Cross-country skiing is widely practiced as a sport and recreational activity; however, some still use it as a means of transportation. Variants of cross-country skiing are adapted to a range of terrain which spans unimproved, sometimes mountainous terrain to groomed courses that are specifically designed for the sport.
- Cross-country running:
Cross country running is a sport in which teams and individuals run a race on open-air courses over natural terrain such as dirt, grass etc. Sometimes the runners are referred to as harriers (dogs). The course, typically 4–12 kilometres (2.5–7.5 mi) long, may include surfaces of grass, and earth, pass through woodlands and open country, and include hills, flat ground and sometimes gravel road. It is both an individual and a team sport; runners are judged on individual times and teams by a points-scoring method. Both men and women of all ages compete in cross country, which usually takes place during autumn and winter, and can include weather conditions of rain, sleet, snow or hail, and a wide range of temperatures.
- Nordic walking:
Nordic walking is a total body version of walking that can be enjoyed both by non-athletes as a health-promoting physical activity, and by athletes as a sport. The activity is performed with specially designed walking poles similar to ski poles.
- Inline skating:
Inline skating or roller blading is a multi-disciplinary sport practiced widely internationally. Inline skates typically have 2 to 5 polyurethane wheels, arranged in a single line by a metal or plastic frame on the underside of a boot. The in-line design allows for greater speed than roller skates and better manoeuvrability. Following this basic design principle, inline skates can be modified to varying degrees to accommodate niche disciplines.
In strength training, rowing (or a row, usually preceded by a qualifying adjective — for instance a seated row) is an exercise where the purpose is to strengthen the muscles that draw the rower's arms toward the body (latissimus dorsi) as well as those that retract the scapulae (trapezius and rhomboids) and those that support the spine (erector spinae). When done on a rowing machine, rowing also exercises muscles that extend and support the legs (quadriceps and thigh muscles). In all cases, the abdominal and lower back muscles must be used in order to support the body and prevent back injury.
Indoor or outdoor
Swimming is primarily a cardiovascular/aerobic exercise due to the long exercise time, requiring a constant oxygen supply to the muscles, except for short sprints where the muscles work anaerobically. As with most aerobic exercise, swimming reduces the harmful effects of stress. Swimming is also effective in improving health for people with cardiovascular problems and chronic illnesses. It is proven to positively impact the mental health of pregnant women and mothers. Swimming can even improve mood.
- Skipping rope or jump rope:
Skipping may be used as a cardiovascular workout, similar to jogging or bicycle riding, and has a high MET or intensity level. This aerobic exercise can achieve a "burn rate" of up to 700 to over 1200 calories per hour of vigorous activity, with about 0.1 to nearly 1.1 calories consumed per jump mainly depending upon the speed and intensity of jumps and leg foldings. Ten minutes of skipping is roughly the equivalent of running an eight-minute mile. Skipping for 15–20 minutes is enough to burn off the calories from a candy bar and is equivalent to 45-60 minutes of running depending upon the intensity of jumps and leg swings. Many professional trainers, fitness experts and professional fighters greatly recommend skipping for burning fat over any other alternative exercises like running and jogging.
- Jumping jacks:
A jumping jack (Canada US) or star jump (UK and other Commonwealth nations), also called side-straddle hop in the US military, is a physical jumping exercise performed by jumping to a position with the legs spread wide and the hands touching overhead, sometimes in a clap, and then returning to a position with the feet together and the arms at the sides.
- Water aerobics:
Water aerobics is the performance of aerobic exercise in fairly shallow water such as in a swimming pool. Done mostly vertically and without swimming typically in waist deep or deeper water, it is a type of resistance training. Water aerobics is a form of aerobic exercise that requires water-immersed participants. Most water aerobics is in a group fitness class setting with a trained professional teaching for about an hour. The classes focus on aerobic endurance, resistance training, and creating an enjoyable atmosphere with music. Different forms of water aerobics include: aqua Zumba, water yoga, aqua aerobics, and aqua jog.
The term running can refer to any of a variety of speeds ranging from jogging to sprinting. Jogging is a form of trotting or running at a slow or leisurely pace. The main intention is to increase physical fitness with less stress on the body than from faster running, or to maintain a steady speed for longer periods of time. Performed over long distances, it is a form of aerobic endurance training.
Sprinting is running over a short distance in a limited period of time. It is used in many sports that incorporate running, typically as a way of quickly reaching a target or goal, or avoiding or catching an opponent.
Among the recognized benefits of doing regular aerobic exercise are:
- Strengthening the muscles involved in respiration, to facilitate the flow of air in and out of the lungs
- Strengthening and enlarging the heart muscle, to improve its pumping efficiency and reduce the resting heart rate, known as aerobic conditioning
- Improving circulation efficiency and reducing blood pressure
- Increasing the total number of red blood cells in the body, facilitating transport of oxygen
- Improved mental health, including reducing stress and lowering the incidence of depression, as well as increased cognitive capacity.
- Reducing the risk for diabetes. One meta-analysis has shown, from multiple conducted studies, that aerobic exercise does help lower Hb A1C levels for type 2 diabetics.
As a result, aerobic exercise can reduce the risk of death due to cardiovascular problems. In addition, high-impact aerobics activities (such as jogging or using a skipping rope) can stimulate bone growth, as well as reduce the risk of osteoporosis for both men and women.
In addition to the health benefits of aerobic exercise, there are numerous performance benefits:
- Increased storage of energy molecules such as fats and carbohydrates within the muscles, allowing for increased endurance
- Neovascularization of the muscle sarcomeres to increase blood flow through the muscles
- Increasing speed at which aerobic metabolism is activated within muscles, allowing a greater portion of energy for intense exercise to be generated aerobically
- Improving the ability of muscles to use fats during exercise, preserving intramuscular glycogen
- Enhancing the speed at which muscles recover from high intensity exercise
- Neurobiological effects: improvements in brain structural connections and increased gray matter density, new neuron growth, improved cognitive function (cognitive control and various forms of memory), and improvement or maintenance of mental health.
Some drawbacks of aerobic exercise include:
- Overuse injuries because of repetitive, high-impact exercise such as distance running.
- It is not an effective approach to building muscle.
- Only effective for fat loss when used consistently.
Both the health benefits and the performance benefits, or "training effect", require a minimum duration and frequency of exercise. Most authorities suggest at least twenty minutes performed at least three times per week.